Novel Colorant Compound and Method of Manufacturing the Same as Well as Blue Resist Composition for Use in Color Filter Containing the Same

ABSTRACT

The present invention provides (I) a method of manufacturing a triphenylmethane colorant that can suppress the sub-reactions in conversion to a sulfonamide and is industrially advantageous, (II) a colorant compound that has both excellent spectral characteristics and a high solubility relative to organic solvents or polymers as a coloring agent to be used in color filters and (III) a blue resist composition for use in a color filter that shows a high lightness and an excellent hue particularly for blue color and can be used to display an image that is excellent in terms of spectral characteristics and contrast.

TECHNICAL FIELD

This invention relates to a novel colorant compound, a method ofmanufacturing such a colorant compound and a blue resist composition foruse in a color filter containing such a colorant compound.

BACKGROUND ART

Generally, in the field of organic synthetic chemistry, a sulfonamidecompound is synthesized by means of a condensation reaction of acorresponding sulfonyl chloride compound and a corresponding amine, andthe sulfonyl chloride compound is synthesized by chlorinating a sulfonicacid group. A similar process is used for forming a sulfonamide for acolorant of a dye or a pigment. A sulfonyl chloride is prepared for acolorant by using chlorosulfonic acid, phosphorus pentachloride orphosphorus trichloride when chlorinating a sulfonic acid group. However,known chlorination techniques are industrially not satisfactory becausethey are accompanied by a problem of sub-reactions that can arise at thetime of chlorinating sulfonic acid groups, which sub-reactions are, forexample, that a sulfonic acid group is introduced anew into the skeletonof the colorant or that the skeleton of the colorant is decomposed.

A method of using thionyl chloride for chlorinating a sulfonic acidgroup is disclosed in an attempt of avoiding such sub-reactions (seeJapanese Patent Application Laid-Open No. H07-242651). However, thecolorant that is the reaction substrate used in the disclosedchlorination technique is a xanthene type colorant and no technique thatis applicable to a triphenylmethane type colorant has been reported sofar.

Meanwhile, the advancement of science and technology has given rise tochanges in the life style and colorants are currently being used invarious industrial fields not only to dye or color various materialssuch as fiber, plastic and leather but also for the purpose of recordingand displaying information. Particularly, as personal computers haverapidly become popular in recent years, there is a rapidly expandingdemand for color liquid crystal displays. Color filters areindispensable for displaying color images on liquid crystal displays andare critical parts to their performances. Additionally, in line with thecurrent dissemination of broadband systems, development of color filtersthat can realize enhanced spectral characteristics and a high contrastratio has become an urgent issue for displaying high definition images.

Known methods for manufacturing color filters include the dyeing method,the printing method, the ink-jet method and the photoresist method.However, the photoresist method has been in the main stream in recentyears because it can control the spectral characteristics of colorfilters in a reproducible manner and allows fine patterning operationsbecause of the high resolution it provides.

Pigments are generally being used as coloring agents with thephotoresist method. However, pigments have a certain size and henceaccompany a depolarization effect. It has been known that the contrastratio of color display of liquid crystal displays is reduced whenpigments are used for coloring agents. Additionally, it is difficult toachieve a high transmission of backlight in a system using pigments topose limits for improving the lightness of color filters. Furthermore,because pigments are insoluble in organic solvents or polymers, coloredresist compositions are obtained in a dispersed state. However, it isdifficult to stabilize the dispersion.

On the other hand, dyes are generally soluble in organic solvents orpolymers and hence stable in colored resist compositions without givingrise to aggregation. Therefore, color filters prepared by using dyes ascoloring agents do not accompany any depolarization effect and canachieve a high transmission of backlight because the dyes are dispersedon a molecular level. Color filters prepared by using dyes have beenreported since they show excellent spectral characteristics and areadapted to display images with an enhanced display contrast.

A method of using C. I. Acid Blue 104, which is a triphenylmethane typecolorant, as a colorant for blue color filters (see Japanese PatentApplication Laid-Open No. 2003-5362) and a method of using C. I. AcidRed 6, which is a monoazo type colorant, as a colorant for red colorfilters (see Japanese Patent Application Laid-Open No. 2003-5361) havebeen disclosed. Of theses methods, the former method of using atriphenylmethane type colorant is particularly advantageous because ofthe high molar absorption coefficient (ε) of the colorant and the vividcolor tone and excellent spectral characteristics.

Furthermore, a method of using an anthraquinone type colorant as acolorant for blue color filters (Japanese Patent Application Laid-OpenNo. 2001-108815) and a method of using a naphthoquinone type colorantalso as a colorant for blue color filters (Japanese Patent ApplicationLaid-Open No. 2002-338839) have been disclosed.

DISCLOSURE OF THE INVENTION

However, the methods described in Japanese Patent Application Laid-OpenNos. 2003-5362 and 2003-5361 are accompanied by such problems that thesolubility of the colorants relative to organic solvents or polymers isinsufficient and hence the colorants can easily be eluted in adevelopment process. On the other hand, the dyes described in JapanesePatent Application Laid-Open Nos. 2001-108815 and 2002-338839 are notsatisfactory although they show a sufficient degree of solubilityrelative to organic solvents or polymers and excellent spectralcharacteristics. Therefore, as discussed above, no colorant that hasboth excellent spectral characteristics and a high solubility relativeto organic solvents or polymers has been reported.

In view of the above-identified circumstances, it is the first object ofthe present invention to provide a method of manufacturing atriphenylmethane type colorant that can suppress the sub-reactions inthe process of forming a sulfonamide and is industrially advantageous.The second object of the present invention is to provide a colorantcompound that has both excellent spectral characteristics and a highsolubility relative to organic solvents or polymers, as a coloring agentto be used in color filters. The third object of the present inventionis to provide a blue resist composition for use in a color filter thatshows a high lightness and an excellent hue particularly for blue colorand can be used to display an image that is excellent in terms ofspectral characteristics and contrast.

According to the present invention, the above objects are achieved byproviding a colorant compound characterized by having a structurerepresented by the general formula (1) shown below:

whereineach of R₁ through R₄ independently denotes a hydrogen atom, an alkylgroup that may be substituted, an aryl group that may be substituted oran aralkyl group that may be substituted, each of R₅ and R₆independently denotes a hydrogen atom or an alkyl group and each of R₇and R₈ independently denotes a hydrogen atom, a sulfonic acid group, anamino group that may be substituted or —SO₂NR₉R₁₀, wherein each of R₉and R₁₀ independently denotes a hydrogen atom, an alkyl group, an arylgroup or an aralkyl group and may form a heterocycle with a nitrogenatom. Additionally, in the general formula (1), n denotes an integerbetween 1 and 3. If neither R₇ nor R₈ is —SO₂NR₉R₁₀, at least one of theR₁ through R₄ is an alkylene group, an arylene group or an aralkylenegroup having —SO₂NR₉R₁₀ as a substituent. In the general formula (1), Andenotes a counter anion, which is not necessary when a counter anionexists in the molecule.

Preferably, in a colorant compound according to the invention as definedabove, the colorant compound has a structure as represented by generalformula (2) shown below:

where R₉ and R₁₀ independently denotes a hydrogen atom, an alkyl group,an aryl group or an aralkyl group and may form a heterocycle with anitrogen atom.

According to the present invention, there is also provided a method ofmanufacturing a sulfonylhalide compound having a structure asrepresented by general formula (4) shown below, which is useful formanufacturing a colorant compound according to the invention. Themanufacturing method comprises a step of causing a colorant compoundhaving a structure as represented by general formula (3) shown below anda thionyl halide to react with each other in the presence ofN,N-dimethylformamide and an organic solvent:

whereineach of R₁ through R₄ independently denotes a hydrogen atom, an alkylgroup that may be substituted, an aryl group that may be substituted oran aralkyl group that may be substituted, each of R₅ and R₆independently denotes a hydrogen atom or an alkyl group, each of R₇ andR₈ independently denotes a hydrogen atom, a sulfonic acid group, anamino group that may be substituted or —SO₃M and n denotes an integerbetween 1 and 3, at least one of the R₁ through R₄ being an alkylenegroup, an arylene group or an aralkylene group having —SO₃M as asubstituent if neither R₇ nor R₈ is —SO₃M. In the general formula (3), Mdenotes a counter cation of a sulfonic group and An denotes a counteranion, although An is not necessary when a counter anion exists in themolecule.

whereineach of R₁ through R₄ independently denotes a hydrogen atom, an alkylgroup that may be substituted, an aryl group that may be substituted oran aralkyl group that may be substituted, each of R₅ and R₆independently denotes a hydrogen atom or an alkyl group, each of R₇ andR₈ independently denotes a hydrogen atom, a sulfonic acid group, anamino group that may be substituted or —SO₃X and n denotes an integerbetween 1 and 3, at least one of the R₁ through R₄ being an alkylenegroup, an arylene group or an aralkylene group having —SO₃X as asubstituent if neither R₇ nor R₈ is —SO₃X. In the general formula (4), Xdenotes a halogen atom and An denotes a counter anion, although An isnot necessary when a counter anion exists in the molecule.

According to the present invention, there is also provided a method ofmanufacturing a colorant compound according to the invention. Amanufacturing method according to the invention comprises a step ofcausing a sulfonylhalide compound having a structure as represented bythe general formula (4) obtained by a method of manufacturing asulfonylhalide compound having a structure as defined above and an aminehaving a structure as represented by general formula (5) below to reactwith each other to conduct condensation reaction:

wherein each of R₉ and R₁₀ independently denotes a hydrogen atom, analkyl group, an aryl group or an aralkyl group and may form aheterocycle with a nitrogen atom.

According to the present invention, there is also provided a blue resistcomposition for use in a color filter comprising a resin or a monomerand at least a colorant compound having a structure as represented bythe above general formula (1).

Thus, the present invention provides a novel colorant compound that isexcellent in terms of spectral characteristics such as colordevelopability and transparency and an industrially advantageous methodof manufacturing such a colorant compound. It is possible to control thesolubility of a novel colorant compound according to the presentinvention relative to organic solvents by changing the type of amines tobe used in the condensation reaction in the process of manufacturing thecolorant compound. The present invention provides a resist compositionfor use in a color filter showing an excellent blue color tone by usingsuch a novel colorant compound.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a ₁H NMR spectrum (400 MHz, CDCl₃, room temperature) of acolorant compound (10) according to the present invention; and

FIG. 2 is a UV visible absorption spectrum of the colorant compound (10)at room temperature when dissolved in cyclohexane.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, the present invention will be described in greater detail byreferring to preferred embodiments of the invention.

As a result of intensive research efforts for solving theabove-identified problems of the prior art, the inventors of the presentinvention found that a colorant compound having a structure asrepresented by the above general formula (1) shows excellent spectralcharacteristics such as color developability and transparency to get tothe present invention. It is possible to control the solubility of acolorant compound as represented by the general formula (1) relative toorganic solvents by changing the type of amines when forming asulfonamide in the process of manufacturing the colorant compound. It isalso possible to provide a color filter showing an excellent blue colortone by using such a colorant compound for a resist composition.

Alkyl groups that can be used for each of R₁ through R₄ in the abovegeneral formulas (1), (3) and (4) include a methyl group, an ethylgroup, an n-propyl group, an isopropyl group, an n-butyl group, asec-butyl group, a tert-butyl group, an n-pentyl group and an n-hexylgroup. Aryl groups that can be used for each of R₁ through R₄ include aphenyl group, a 1-naphthyl group and a 2-naphthyl group. Aralkyl groupsthat can be used for each of R₁ through R₄ include a benzyl group and aphenethyl group. R₁ and R₃ (or R₁ and R₄) may be the same with ordifferent from each other, and R₂ and R₄ (or R₂ and R₃) may be the samewith or different each other, although they are preferably the same fromthe viewpoint of color tone and raw material cost. It is particularlypreferable that they are all ethyl groups or that R₁ and R₃ (or R₁ andR₄) are ethyl groups and R₂ and R₄ (or R₂ and R₃, whichever appropriate)are benzyl groups. These substituents may be substituted by SO₂NR₉R₁₀.

Alkyl groups that can be used for each of R₅ and R₆ in the above generalformulas (1), (3) and (4) include a methyl group, an ethyl group, ann-propyl group and an isopropyl group. Preferably, each of R₅ and R₆ maybe either a hydrogen atom or a methyl group.

The amino group of each of R₇ and R₈ in the above general formulas (1),(3) and (4) may be substituted by an alkyl group such as a methyl groupand an ethyl group, a phenyl group, a methoxyphenyl group, anethoxyphenyl group or a benzenesulfonic acid group. R₉ and R₁₀ in theabove general formula (1) correspond to a substitution residue group ofan amine represented by the above general formula (5).

Since R₉ and R₁₀ in the above general formula (5) significantlyinfluence the solubility of a colorant compound represented by thegeneral formula (1), it is possible to obtain a colorant compoundshowing a desired level of solubility by changing the substituent ofeach of R₉ and R₁₀. Examples of substituents that can be used for eachof R₉ and R₁₀ include chain or cyclic alkyl groups such as a methylgroup, an ethyl group, an n-propyl group, an isopropyl group, an n-butylgroup, a sec-butyl group, a tert-butyl group, an n-pentyl group, ann-hexyl group, an n-pentyl group, an n-octyl group, a 2-echylhexyl groupand a cyclohexyl group as well as aryl groups such as a phenyl group a1-naphthyl group and a 2-naphthyl group and aralkyl groups such as abenzyl group and a phenethyl group.

Each of R₉ and R₁₀ may form a heterocycle with a nitrogen atom. Specificexamples of such heterocyclic groups include a piperazino group, apiperidino group, a pyrrole group, an indol group, a carbazole group, apyrazole group, an indazole group, an imidazole group, a benzimidazolegroup, a triazole group, a benzotriazole group and a tetrazole group.From the viewpoint of reactivity for sulfonamidation, it is, preferablethat the substituent of each of R₉ and R₁₀ shows a small sterichindrance because the reactivity of, the general formula (5) is highwhen such a substituent is used and a colorant compound represented bythe general formula (1) can be produced at a high yield. From theviewpoint of solubility for organic solvents, it is preferable that eachof R₉ and R₁₀ is a long chain alkyl group or the like that is highlyoil-soluble.

Now, a method of manufacturing a novel colorant compound to be used forthe purpose of the present invention will be described below. The methodof manufacturing a colorant compound according to the present inventioncomprises a step of obtaining a sulfonylhalide having a structurerepresented by the general formula (4) as mentioned above byhalogenization of a sulfonic group in a colorant compound represented bythe general formula (3) as described above and a step of subsequentlyobtaining a colorant compound represented by the above general formula(1) by causing a condensation reaction to take place between thesulfonylhalide compound and an amine having a structure represented bythe above general formula (5).

Specific examples of M in the general formula (3) include a hydrogenatom and a metal ion such as a sodium ion, a lithium ion and a potassiumion. Specific examples of X in the general formula (4) include halogenatoms such as a chlorine atom and a bromine atom.

Specific examples of colorant compounds having a structure representedby the general formula (3) non-limitatively include those having astructure represented by any of general formulas (6) through (9) listedbelow.

wherein M denotes a counter cation of a sulfonic group as in the abovegeneral formula (3).

Any of the above colorant compounds is caused to react with a thionylhalide by itself or as a mixture of two or more than two such colorantcompounds. Thionyl chloride is preferable among thionyl halides. The useof a solvent of a halogenated aliphatic hydrocarbon compound ispreferable as a reaction solvent. Specific examples of halogenatedaliphatic hydrocarbons include chloroform, methylene chloride, carbontetrachloride, 1,2-dichloroethane, dichloroethylene, trichloroethylene,perchloroethylene, dichloropropane, amyl chloride, dichloropentane,tetrachloroethane and 1,2-dibromoethane, of which chloroform ispreferable.

In the reaction of a colorant compound represented by the generalformula (3) with thionyl halide, the amount ratio of thionyl halide (A)relative to N,N-dimethylformamide (B), or A:B, is preferably within arange between 1:0.3 and 1:0.8. While the amount of thionyl halide (A)varies depending on the type and the purity of the colorant compound (C)to be used, the amount ratio of thionyl halide (A) relative to thecolorant compound (C) to be used, or A:C, is normally within a rangebetween 1:1 and 1:20. Generally speaking, the amount of thionyl halideto be used may be stoichiometrically equivalent or slightly excessivewhen the colorant compound shows a high degree of purity. On the otherhand, thionyl halide is preferably used in an amount that isstoichiometrically much excessive when the colorant compound shows a lowcolorant purity because it contains impurities such as common saltand/or mirabilite to a large extent. The reaction is normally conductedby gradually dropping thionyl halide into a mixture of a colorantcompound of the general formula (3), N,N-dimethylformamide and a solventof a halogenated aliphatic hydrocarbon compound. The reactiontemperature is normally between about 0° C. and about 70° C., preferablybetween about 30° C. and 60° C., and the reaction time is normallybetween 30 minutes and 6 hours. The amount of a halogenated aliphatichydrocarbon compound is used may be selected appropriately.

The sulfonylhalide compound represented by the general formula (4) isnormally taken out form the reaction mixture by means of a conventionaltechnique including extraction, washing and condensation, if necessaryafter cooling the reaction mixture, after decomposing the remainingthionyl halide by pouring the mixture into water or ice water.Preferably, the obtained reaction mixture (the solvent solution of ahalogenated aliphatic hydrocarbon compound containing the sulfonylhalidecompound and the remaining thionyl halide) is subjected to thecondensation reaction with the amine represented by the above generalformula (5) without further treatment.

The condensation reaction of the sulfonylhalide compound represented bythe general formula (4) and the amine represented by the general formula(5) is conducted preferably in the presence of a basic catalyst, whichmay typically be an aliphatic or aromatic amine. Specific examples ofaliphatic or aromatic amines that can be used as a basic catalyst forthe condensation reaction include triethylamine, pyridine, piperidine,piperazine and triethanolamine. The use of a tertiary amine ispreferable. When the reaction mixture is subjected to a reaction withthe amine represented by the general formula (5) without furthertreatment and a basic catalyst is used, the molar ratio of the totalamount (D) of the amine represented by the general formula (5) and theabove described basic catalyst relative to the amount (A) of thionylhalide to be used in the above reaction, or D:A, is preferably within arange between 1:2.2 and 1:2.5.

When a basic catalyst is used, the molar ratio of the catalyst (E)relative to the amine (F) represented by the general formula (5), orE:F, is within a range between 1:0.5 and 1:1.5, preferably between 1:0.8and 1:1.2. The amount of the condensation reaction solvent such as ahalogenated aliphatic hydrocarbon compound to be used may be selectedappropriately. The condensation reaction temperature is normally between0° C. and 60° C., preferably between 5° C. and 40° C., and the reactiontime is normally between 30 minutes and 6 hours. The colorant compoundrepresented by the general formula (1) is normally taken out from thecondensation reaction mixture by means of a conventional techniqueincluding neutralization, extraction, washing and condensation, ifnecessary after cooling the reaction mixture. Preferably, a technique ofcondensing the solvent and refining it by recrystallization or by meansof column chromatography after the neutralization, the extraction andthe washing may be used.

A colorant compound according to the invention shows a clear blue colortone and can suitably be used as a coloring material, preferably as acoloring agent for color filters because of its spectralcharacteristics. More specifically, it can be used as a material forpreparing a blue resist composition as well as a printing ink, paint andwriting ink.

Now, a blue resist composition for use in a color filter according tothe present invention will be described below.

A blue resist composition according to the invention contains at leasteither one of binder resin and a photo-polymerizing monomer and acolorant compound as represented by the above general formula (1).Preferably, a blue resist composition according to the invention furthercontains a photo-polymerization initiator and a solvent.

In a color filter formed by arranging two or more different types ofpixels having different spectral characteristics on a substrate, atleast one of the pixels (e.g., red, green or blue) can be made to show ahigh degree of transparency and color purity by using a colorantcompound according to the invention as represented by the generalformula (1). Additionally, since the spectral characteristics can beimproved by using a mixture of a pigment and a dye, a mixture of apigment and a colorant compound according to the present invention maybe used for a color filter. Additionally, some other dye may beadditionally used as a color adjusting agent to regulate the spectralcharacteristics. A colorant to be used for a color filter that containsa colorant compound according to the present invention may be eitherwater-soluble or oil-soluble. While it is preferable that the dye iscompletely dissolved, it is not necessary to dissolve the dye if it canbe dispersed as sufficiently fine particles. Thus, many commerciallyavailable coloring agents may selectively be used for the purpose of thepresent invention.

Specific examples of colorants that can be used as color adjustingagents for a color filter according to the present inventionnon-limitatively include Acid Red 52, 87, 92, 122 and 486, Solvent Red8, 24, 83, 109, 125 and 132, Disperse Red 60, 72, 88 and 206, Basic Red12 and 27, Acid Blue 1, 7, 9, 40, 83, 90, 129 and 249, Solvent Blue 25,35, 36, 55, 67 and 70, Disperse Blue 56, 81, 60, 87, 149, 197, 211 and214, Basic Blue 1, 7, 26 and 77, Acid Green 18, Solvent Green 3, BasicGreen 1, Acid Yellow 38 and 99, Solvent Yellow 25, 88, 89 and 146,Disperse Yellow 42, 60, 87 and 198 and Basic Yellow 21.

Specific examples of pigments that can be used for a color filteraccording to the present invention non-limitatively include Pigment Red9, 19, 38, 43, 97, 122, 123, 144, 149, 166, 168, 177, 179, 180, 192,208, 215, 216, 217, 220, 223, 224, 226, 227, 228 and 240, Pigment Blue15, 15:6, 16, 22, 29; 60 and 64, Pigment Green 7 and 36, Pigment Yellow20, 24, 81, 83, 86, 93, 108, 109, 110, 117; 125, 137, 138, 139, 147,148, 153, 154, 166, 168 and 185, Pigment Orange 36 and Pigment Violet23. Two or more of these dyes or pigments may be mixed for use in orderto achieve a desired hue.

The content of a colorant compound as represented by the above generalformula (1) is preferably between 0.1 and 400 mass %, more preferablybetween 1 and 200 mass % relative to the mass of the binder resin, whichwill be described in greater detail hereinafter.

While no particular limitations are posed to the binder resin to be usedfor a blue resist composition in a color filter according to the presentinvention so long as the light irradiation portion or the lightshielding portion thereof is soluble in an organic solvent, an aqueousalkali solution, water or a commercially available developer, the use ofbinder resins having a composition that can be developed in water oralkali is desirable from the viewpoint of handling and waste disposal.

Such binder resins include those obtained by copolymerizing hydrophilicmonomers such as those having (meth)acrylic acid, 2-hydroxyethyl, acrylamide, N-vinylpyrrolidone, or an ammonium salt and lipophilic monomerssuch as a (meth)acrylate, vinyl acetate, styrene or N-vinylcarbazole atan appropriate mixing ratio by way of a known process. Such a binderresin can be used as resist of the negative type whose light shieldingportion can be removed by development when combined withradical-polymerizing monomers having an ethylenically unsaturated groupor cation-polymerizing monomers having an oxirane ring or an oxetanering and a radical generator, an acid generator or a base generator.

Alternatively, a binder resin selected from tert-butyl carbonate,tert-butylester, tetrahydroxypyranyl ester or tetrahydroxypyranyl etherof polyhydroxystyrene may be used. Such a binder resin can be used as aresist of the positive type whose light irradiation portion can beremoved by development when combined with an acid generator.

A blue resist composition for use in a color filter may contain aphoto-polymerizing monomer having one or more ethylenically unsaturateddouble bonds as a monomer having an ethylenically unsaturated doublebond to be used for addition polymerization by way of irradiation oflight. Such a photo-polymerizing monomer may be selected from compoundshaving at least one ethylenically unsaturated group that can be used foraddition polymerization in the molecule and a boiling point of not lowerthan 100° C. under the atmospheric pressure. Examples of such compoundsinclude monofunctional (meth)acrylates such aspolyethyleneglycolmono(meth)acrylate,polypropyleneglycolmono(meth)acrylate and phenoxyethyl(meth)acrylate,polyfunctional (meth)acrylates such aspolyethyleneglycoldi(meth)acrylate, polypropyleneglycoldi(meth)acrylate,trimethylolethanetri(meth)acrylate, trimethylolpropanetri(meth)acrylate,trimethylolpropanedi(meth)acrylate, neopentylglycoldi(meth)acrylate,pentaerithritoltetra(meth)acrylate, pentaerithritoltri(meth)acrylate,dipentaerithritolhexa(meth)acrylate,dipentaerithritolpenta(meth)acrylate, hexanediol(meth)acrylate,trimethyrolpropanetri(acryloyloxypropyl)ether,tri(acryloyloxyethyl)isocyanurate, tri(acryloyloxyethyl)cyanurate andglycerintri(meth)acrylate and polyfunctional acrylates andpolyfunctional methacrylates obtained by adding ethylene oxide orpropylene oxide to a polyfunctional alcohol such as trimethylolpropaneor glycerin and subsequently turning it into a (meth)acrylate.

Examples of such compounds further include urethane acrylates, polyesteracrylates, epoxy acrylates that are reaction products of epoxy resinsand (meth)acrylic acids and other polyfunctional (meth)acrylates. Of theabove listed examples, trimethylolpropanetri(meth)acrylate,pentaerithritoltetra(meth)acrylate anddipentaerithritolhexa(meth)acrylate,dipentaerithritolpenta(meth)acrylate are preferable.

A photo-polymerizing monomer having two or more ethylenicallyunsaturated double bonds may be used alone or two or more of them may bemixed for use. The content of the polymerizing compound is generallybetween 5 and 50 mass % relative to the mass of the coloringphotosensitive composition (total solid component), preferably between10 and 40 mass %. The photosensitivity and the strength of the pixelscan be reduced when the content falls below 5 mass %, whereas thestickiness of the photosensitive resin layer can become too much whenthe content exceeds 50 masse.

A blue resist composition for use in a color filter is so composed as tocontain a photo-polymerization initiator when it is cured by ultravioletrays. Photo-polymerization initiators that can be used for the purposeof the present invention include vicinalpolyketoaldonyl compounds,α-carbonyl compounds, acyloin ethers, multi-branch quinone compounds,combinations of a triarylimidazole dimer and a p-aminophenylketone, andtrioxadiazole compounds, among which2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (IRGACURE 369:tradename, available from Ciba Specialty Chemicals) is preferable. Theuse of a photo-polymerization initiator is not indispensable whenelectron beams are used to form pixels by means of the colored resistaccording to the present invention.

A blue resist composition for use in a color filter according to thepresent invention contains a solvent for dissolving or dispersing thebinder resin, the photo-polymerizing monomer, the photo-polymerizationinitiator, the coloring agent and so on, which are described above.Solvents that can be used for the purpose of the present inventioninclude cyclohexanone, ethyl cellosolve acetate, butyl cellosolveacetate, 1-methoxy-2-propylacetate, diethylene glycol dimethyl ether,ethyl benzene, 1,2,4-trichlorobenzene, ethylene glycol diethyl ether,xylene, ethyl cellosolve, methyl-n-amyl ketone, propylene glycolmonomethyl ether, toluene, methyl ethyl ketone, ethyl acetate, methanol,ethanol, isopropyl alcohol, butanol, isobutyl ketone and petroleum typesolvents. These solvents may be used alone or in combination of two ormore of them.

As described above, since a blue resist composition for use in a colorfilter according to the present invention contains a colorant compoundas represented by the above general formula (1) as a coloring agent, thepixels formed by using it show an excellent hue and an improvedtransparency as well as an improved light transmittance.

EXAMPLES

Now, the present invention will be described further in greater detailby way of examples and comparative examples, although the presentinvention is by no means limited to the examples. In the followingdescription, “parts” and “%” are parts by mass and mass % unless notedotherwise.

Example 1

A colorant compound having a structure as represented by the abovegeneral formula (1) is obtained in a manner as described below.

Synthesis Example Manufacturing a Colorant Compound as Defined byGeneral Formula (10) Shown Below

5.1 mL of thionyl chloride was dropped into a mixture of 10 g of acolorant compound represented by the above general formula (6), where Mis sodium salt, 80 mL of chloroform and 2.4 g of N,N-dimethylformamide,over one hour, at room temperature. After completing the dropping, thetemperature of the solution was raised to 60° C. and stirred for 3 hoursat this temperature. Then, a mixture of 15.5 g of di(2-ethylhexyl)amineand 7.7 g of triethylamine was dropped into the obtained reactionmixture, over one hour at 0° C. After completing the dropping, thetemperature of the solution was raised to 60° C. and stirred for 3 hourat this temperature. After the completion of the reaction, the reactionmixture was neutralized by acetic acid and poured into 250 mL of water.Then, the reaction mixture was subjected to an extraction process byusing chloroform and the organic layer was washed with 250 mL of water.After drying the organic layer by means of anhydrous mirabilite, theprecipitate was filtered and the solvent in the filtration liquid wasdistilled off. Then, the distillation residue was refined by means ofcolumn chromatography to obtain a compound represented by the formula(10).

The structure of the compound was identified by means ₁H and ₁₃C NMRanalysis, using a nuclear magnetic resonance spectrochemical analyzer(ECA-400: tradename, available from JEOL), and the purity of theobtained compound was checked by means of HPLC (high performance liquidchromatography, LC2010A: tradename, available from SHIMADZU). Theresults of the analysis are shown below.

(results of analysis of compound represented by formula (10))(1) Results of ₁H NMR (400 MHz, CDCl₃, room temperature) (FIG. 1):

δ=0.80-0.89 (m, 24H), 1.22-1.39 (m, 42H), 2.81-3.00 (m, 8H), 3.60-3.70(m, 4H), 4.75-4.85 (m, 4H), 6.77-6.79 (m, 4H), 6.95 (dd, 1H), 7.32 (d,1H), 7.38 (m, 2H), 7.49-7.57 (m, 7H), 7.62 (br, 2H), 7.69-7.75 (m, 2H),8.31 (d, 1H)

(2) Results of ₁₃C NMR (100 MHz, CDCl₃, room temperature):δ=10.1, 12.5, 14.0, 23.0, 23.4, 28.6, 30.3, 37.7, 46.6, 53.4, 113.2,125.2, 126.6, 126.8, 128.0, 128.7, 129.1, 130.0, 130.1, 130.3, 130.4,136.2, 137.0, 140.4, 141.7, 147.4, 156.1, 182.1(3) Results of HPLC: purity=96.7 area %, retention time: 9.3 minutes(MeOH/H₂O=95/5)

A series of colorant compounds represented by the above general formula(2) were synthesized by using the manufacturing method in the abovedescribed synthesis example. Tables 1 and 2 below illustrate R₉ and R₁₀in the synthesized series of colorant compounds. Colorant compounds werealso synthesized by way of a similar process except that colorantcompounds represented by the above general formulas (7) through (9) wereused in place of the colorant compound represented by the generalformula (6). The series of the synthesized colorant compounds are listedin Table 3 below.

Example 2 Evaluation of Solubility of Colorant Compounds

The solubility of each of the series of the synthesized colorantcompounds (10) through (27) to cyclohexanone was evaluated by referringto the ranking system shown below. As compounds for comparison, those inwhich M of the colorant compound represented by the above generalformula (6) was sodium salt were also evaluated in a similar manner.Tables 1 through 3 also show the obtained results.

A: The solubility to cyclohexanone is not lower than 10%.

B: The solubility to cyclohexanone is not lower than 5% and lower than10%.

C: The solubility to cyclohexanone is lower than 5%.

TABLE 1 Evaluation of Solubility of Colorant Compounds of Formulas (10)through (18) to Cyclohexanone compound solu- No. R₉ R₁₀ bility (10)C₄H₉CH(C₂H₅)CH₂— C₄H₉CH(C₂H₅)CH₂— Ā (11) C₆H₁₃— C₆H₁₃— A (12)

A (13) (CH₃)₂CH₂— (CH₃)₂CH₂— B (14) C₂H₅—

B (15)

A (16)

B (17)

B (18)

B

TABLE 2 Evaluation of Solubility of Colorant Compounds of Formulas (19)through (24) to Cyclohexanone compound solu- No. R₉ R₁₀ bility (19)

B (20)

B (21)

B (22)

B (23)

B (24)

B

TABLE 3 Evaluation of Solubility of Colorant Compounds of Formulas (6)and (25) through (27) to Cyclohexanone colorant compound compound No.used R₉ R₁₀ An solubility  (6) — — — — C (25) (7) C₄H₉CH(C₂H₅)CH₂—C₄H₉CH(C₂H₅)CH₂— — A (26) (8) C₄H₉CH(C₂H₅)CH₂— C₄H₉CH(C₂H₅)CH₂— — A (27)(9) C₄H₉CH(C₂H₅)CH₂— C₄H₉CH(C₂H₅)CH₂— Cl A

From the results listed in Tables 1 through 3, it was found that acolorant compound represented by the general formula (1) according tothe present invention shows a dramatically improved solubility tocyclohexanone because of its sulfonamide group if compared with acolorant compound represented by the general formula (3). This factsuggests that it is possible to obtain a resist composition that doesnot give rise to aggregation and remains stable when used for a coloringagent by using a colorant compound having a sulfonamide group accordingto present invention. A colorant compound as represented by the generalformula (1) shows an excellent solubility to cyclohexanone particularlywhen R₉ and R₁₀ are alkyl groups, long chain alkyl groups in particular.

Example 3 Evaluation of Spectral Characteristics of Colorant Compounds

The colorant compounds represented by the formula (10) was dissolved incyclohexanone and regulated so as to show an absorbance of 2.0. Theobtained solution was observed for UV visible absorption spectrum atroom temperature by means of a spectro photometer (U-3310 SpectroPhotometer: tradename, available from Hitachi) (FIG. 2). The absorptionpeak wavelength (λ_(max) [nm]) was determined from the spectrum obtainedby the observation. The spectral characteristics of the colorantcompound were evaluated by the absorbance ratio of the largestabsorption wavelength of the spectrum in the range of 500 to 650 nm tothe smallest absorption wavelength of the spectrum in the range of 400to 500 nm (the absorbance at the largest absorption wavelength/theabsorbance at the smallest absorption wavelength). It is possible toprepare a color filter having pixels that show a high degree oflightness when the absorbance ratio is large.

While the lightness can be evaluated by means of the Y value of the XYZstandard calorimetric system established by CIE (CommissionInternationale de l'Eclairage), the lightness was evaluated by means ofthe absorbance ratio in this example because the Y value can varyremarkably when the hue is shifted slightly.

The same evaluation process as described above was conducted forspectral characteristics except that the colorant compound representedby the formula (10) was replaced with the colorant compounds representedby the formulas (14), (25) through (27) and (28), the colorant compoundrepresented by the formula (28) being an anthraquinone type dye of C. I.Solvent Blue 35. The obtained results are summarily listed in Table 4below.

TABLE 4 Results of Evaluation of Spectral Characteristics compound No.λ_(max) [nm] absorbance ratio (10) 619 433 (14) 620 434 (25) 631 185(26) 617 140 (27) 621 130 (28) 620 77

From the results listed in Table 4 and by comparing the formulas (10)and (14), it was found that the colorant compounds having the samecolorant skeleton do not show any remarkable difference in terms ofspectral characteristics. Additionally, the series of the colorantcompounds represented by the general formula (1) show spectralcharacteristics much better than the colorant compound (28) that is ananthraquinone type colorant. Particularly, the colorant compounds havinga colorant skeleton represented by the above general formula (2) show anexcellent lightness and also excellent spectral characteristics whenused as coloring agents for color filters.

Example 4 Preparation of Blue Resist Composition

2.0 parts of the colorant compound (10) obtained in Synthesis Example 1was added to 6.7 parts of an acryl copolymer composition, 1.3 parts ofdipentaerithritol penta(meth)acrylate, 0.4 parts of2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1(photo-polymerization initiator) and 116 parts of cyclohexane and themixture was stirred at room temperature for 3 hours. A blue resistcomposition was obtained by filtering the resultant mixture by means ofa 1.5 μm filter.

Example 5 Preparation of an Applied Sample

The blue resist composition obtained by means of the above-describedprocess was applied to a glass plate by spin coating and dried at 90° C.for 3 minutes. Subsequently, the entire surface was exposed to light andsubjected to a post curing process at 180° C. to prepare an appliedsample. The applied sample showed excellent transmission and color tone.

INDUSTRIAL APPLICABILITY

A colorant compound according to the invention can be applicable to avariety of uses because it is highly soluble in organic solvents and thesolubility can be easily controlled depending on the use by changing thetype of amines to be used for solfonamidation. Thus, a colorant compoundaccording to the invention can be applicable not only for use incoloring agents but also in electronic materials such as opticalrecording colorants because of its remarkable physical properties.

This application claims priority from Japanese Patent Application No.2005-037416 filed on Feb. 15, 2005, which is hereby incorporated byreference herein.

1. A colorant compound having a structure represented by the generalformula (1) below:

wherein each of R₁ through R₄ independently denotes a hydrogen atom, analkyl group that may be substituted, an aryl group that may besubstituted or an aralkyl group that may be substituted, each of R₅ andR₆ independently denotes a hydrogen atom or an alkyl group and each ofR₇ and R₈ independently denotes a hydrogen atom, a sulfonic acid group,an amino group that may be substituted or —SO₂NR₉R₁₀, wherein each of R₉and R₁₀ independently denotes a hydrogen atom, an alkyl group, an arylgroup or an aralkyl group and may form a heterocycle with a nitrogenatom; n denotes an integer between 1 and 3; if neither R₇ nor R₈ is—SO₂NR₉R₁₀, at least one of the R₁ through R₄ is an alkylene group, anarylene group or an aralkylene group having —SO₂NR₉R₁₀ as a substituent;and An denotes a counter anion, which is not necessary when a counteranion exists in the molecule.
 2. The colorant compound according toclaim 1 having a structure represented by the general formula (2) below:

wherein each of R₉ and R₁₀ independently denotes a hydrogen atom, analkyl group, an aryl group or an aralkyl group and may form aheterocycle with a nitrogen atom.
 3. A method of manufacturing asulfonylhalide compound having a structure represented by generalformula (4) below, comprising a step of causing a colorant compoundrepresented by the general formula (3) below and thionyl halide to reactwith each other in the presence of N,N-dimethylformamide and an organicsolvent:

wherein each of R₁ through R₄ independently denotes a hydrogen atom, analkyl group that may be substituted, an aryl group that may besubstituted or an aralkyl group that may be substituted, each of R₅ andR₆ independently denotes a hydrogen atom or an alkyl group, each of R₇and R₈ independently denotes a hydrogen atom, a sulfonic acid group, anamino group that may be substituted or —SO₃M; n denotes an integerbetween 1 and 3; at least one of the R₁ through R₄ is an alkylene group,an arylene group or an aralkylene group having —SO₃M as a substituent ifneither R₇ nor R₈ is —SO₃M; M denotes a counter cation of a sulfonicgroup; and An denotes a counter anion, although An is not necessary whena counter anion exists in the molecule,

wherein each of R₁ through R₄ independently denotes a hydrogen atom, analkyl group that may be substituted, an aryl group that may besubstituted or an aralkyl group that may be substituted, each of R₅ andR₆ independently denotes a hydrogen atom or an alkyl group, each of R₇and R₈ independently denotes a hydrogen atom, a sulfonic acid group, anamino group that may be substituted or —SO₃X; n denotes an integerbetween 1 and 3; at least one of the R₁ through R₄ is an alkylene group,an arylene group or an aralkylene group having —SO₃X as a substituent ifneither R₇ nor R₈ is —SO₃X; X denotes a halogen atom; and An denotes acounter anion, although An is not necessary when a counter anion existsin the molecule.
 4. A method of manufacturing a colorant compound,comprising a step of causing a sulfonylhalide compound having astructure as represented by the general formula (4) below and an aminehaving a structure as represented by the general formula (5) below toreact with each other to conduct condensation reaction:

wherein each of R₁ through R₄ independently denotes a hydrogen atom, analkyl group that may be substituted, an aryl group that may besubstituted or an aralkyl group that may be substituted, each of R₅ andR₆ independently denotes a hydrogen atom or an alkyl group, each of R₇and R₈ independently denotes a hydrogen atom, a sulfonic acid group, anamino group that may be substituted or —SO₃X; n denotes an integerbetween 1 and 3; at least one of the R₁ through R₄ is an alkylene group,an arylene group or an aralkylene group having —SO₃X as a substituent ifneither R₇ nor R₈ is —SO₃X; X denotes a halogen atom; and An denotes acounter anion, although An is not necessary when a counter anion existsin the molecule,

wherein each of R₉ and R₁₀ independently denotes a hydrogen atom, analkyl group, an aryl group or an aralkyl group and may form aheterocycle with a nitrogen atom.
 5. A blue resist composition for usein a color filter comprising a resin or a monomer and a colorantcompound according to claim 1.